BIG BAR LANDSLIDE UPDATE SEPTEMBER 18, 2020

Response Webpage BC River Forecast

UPDATE CONTINUES ON PAGE 2

This past week marked the arrival of coho, the last of the migrating salm-on, at Lillooet on their way up-stream. With water levels remaining low along the Fraser River, coho are expected to migrate past the slide site on their own.

The concrete fish ladder that attracts fish to an elevated holding pool will remain on standby for the remainder of the coho migration season. If river levels rise drastically, crews will assist the passage of coho via ‘truck and transport’.

Over the last several weeks, moni-toring teams have confirmed that fish are migrating past the slide site without any assistance. As a result, Whooshh Passage Portal™ opera-tions concluded as of September 8 and preparations are underway to disassemble the system.

TOP: All monitoring data over the last sev-

eral weeks confirm that fish are migrating

past the slide site without any

assistance.

BOTTOM: With the majority of fish swim-

ming past the slide site on their own, the

Whooshh Passage Portal™ is now being

disassembled. Here, a crew member dis-

connects the flex hose that supplied water

to the Whooshh™ and concrete fish

ladder.

As of September 2020, the Big Bar Landslide Response Information Bulletin will be published on a bi-weekly basis to coincide

with the scale of operations onsite.

COHO SALMON EXPECTED TO ARRIVE AT BIG BAR LANDSLIDE SITE

BIG BAR LANDSLIDE UPDATE SEPTEMBER 18, 2020

Response Webpage BC River Forecast

BIG BAR SALMON COUNTS

SALMON RADIO

TAGGED BELOW

BIG BAR LANDSLIDE

WHOOSHH PASSAGE

PORTAL TM

TRUCK AND TRANSPORT

SALMON 40 KM UPSTREAM

OF BIG BAR LANDSLIDE

TOTAL TO DATE 8273 1527

NATIVE FISH PASSAGESALMON USING ALTER

Daily updated counts online

UPDATE ON FISH MONITORING

In the past two weeks, the fish wheel operation led by the Gitxsan Watershed Authorities in collabora-tion with St’at’imc Eco Resources has been relocated from the slide site to Lillooet and positioned approxi-mately 5 km downstream. It is now being used to capture fish for the radio tagging program.

Fish wheel operation began on September 8 and, to date, 44 chinook, 133 sockeye and 46 coho have been radio tagged. All tagged salmon appear in good condition and a few larger than expected chinook were also tagged this past week. The fish wheel will be in use until late October, when the majority of coho are expected to have passed through Lillooet.

UPDATE CONTINUES ON PAGE 3

LEFT: A fish technician applying a radio tag to a large chinook. RIGHT: Radio tagged chinook released back into the Fraser River.

past week.the Lillooet seining site and at the fish wheel this chinook have been observed throughout August at salmon that mature and return one year early. Jack in large numbers at both sonar sites. These are male week, Jack chinook and sockeye have been detected observed at the Churn Creek sonar site. In the last of September 16, over 145,000 salmon have been stream slows between now and late September. As slide site as the chinook and sockeye migration up- a decrease in the number of fish moving past the In recent weeks, hydro acoustic monitoring indicates

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PICTURED: The concrete fish ladder will remain in place to sup-

port ‘truck and transport’ operations, if required, throughout

the coho migration season.

BIG BAR LANDSLIDE UPDATE SEPTEMBER 18, 2020

Response Webpage BC River Forecast

COHO – BIG BAR’S LAST MIGRATING SALMON SPECIES

Coho, the last of the salmon species expected through the Big Bar landslide site this season, are finally making the long journey up the Fraser River towards their natal streams.

They migrate up the Fraser each year between mid-September and early November where they spawn until early winter, right behind their “cousins” – the chinook, sockeye and, in alternating years, pink stocks. Of all the coho spawners on the Fraser and Thompson rivers, only 10 to 15 percent migrate through the Big Bar area. The majority are found throughout the Thompson River, the largest water-shed in the Fraser River system. Tsilhqot'in National Government and Northern Shuswap Tribal Council, in partnership with DFO, are undertaking work in the Chilcotin and Quesnel basins to improve coho moni-toring.

When fry emerge from the gravel in the spring, juve-niles rear in side-channels, stream margins and occa-sionally lakes. They remain in freshwater for a year and then migrate downstream as smolts, spending time in the Fraser estuaries before swimming towards the ocean. Interior Fraser coho spend 18 months at sea before returning to freshwater in the autumn, completing their three-year life cycle.

Fraser River coho salmon are known to migrate ex-tensively in the Pacific and have been caught in Alas-ka and California. However, the majority are found near the coast of southern BC and Washington state, and in the Salish Sea. Since 1994, Interior Fraser coho productivity and survival rates have seen steep de-clines which may be due to a variety of factors such as changing marine conditions and changes in fresh-water habitats due to land use and climate change.

The Committee on Status of Endangered Wildlife in Canada (COSEWIC) has assessed many of the Fraser

salmon populations and has designated the Interior Fraser coho as threatened. The work being done at Big Bar to restore natural fish passage is key to en-suring the long term survival of these stocks.

Adult coho weigh approximately 2-5 kg and measure 45-70 cm, rivalling their sockeye “cousins” in size despite being the younger of the two. They are known fighters and given the current low water lev-els along the Fraser, coho are largely expected to migrate past the slide site without the support of alternative fish passage systems.

They may be the last to arrive, but coho, like all salmon, play a life-sustaining role within the ecosys-tem in British Columbia. Coho in particular serve as the last source of critical nutrients for the rivers and the wildlife that rely on them before winter begins. Together with our First Nations and provincial part-ners, we remain committed to protecting these iconic species.